nandi.uk
Fork of daniellemaywood.uk/gleam — Wasm codegen work
Improve parser diagnostics for incomplete @external attributes
author
Asish Kumar
committer
Louis Pilfold
date
(Jul 3, 2026, 8:53 PM +0100)
commit
6cdff315
6cdff315ece6e228940a24c8e309ae4d4f9c8392
parent
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2aca550cea966d5534303cce8009f4acc01709d7
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CHANGELOG.md
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CHANGELOG.md
···
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deprecated.
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([Surya Rose](https://github.com/GearsDatapacks))
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- The compiler now gives a better error message when an `@external`
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attribute is incomplete. For example:
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```gleam
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@external
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pub fn wibble()
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```
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now points to the attribute itself and explains that it is incomplete.
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([Asish Kumar](https://github.com/officialasishkumar))
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### Build tool
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- The build tool now generates Hexdocs URLs using the new format of
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compiler-core/src/parse.rs
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compiler-core/src/parse.rs
···
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let end = match name.as_str() {
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"external" => {
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let _ = self.expect_one(&Token::LeftParen)?;
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let _ = self.maybe_one(&Token::LeftParen).ok_or(ParseError {
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error: ParseErrorType::ExpectedExternalArguments,
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location: SrcSpan { start, end },
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})?;
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self.parse_external_attribute(start, end, attributes)
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}
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"target" => self.parse_target_attribute(start, end, attributes),
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compiler-core/src/parse/error.rs
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compiler-core/src/parse/error.rs
···
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ExpectedValue, // no value after "="
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ExpectedDefinition, // after attributes
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ExpectedDeprecationMessage, // after "deprecated"
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ExpectedExternalArguments, // after "@external"
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ExpectedFunctionDefinition, // after function-only attributes
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ExpectedTargetName, // after "@target("
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ExprLparStart, // it seems "(" was used to start an expression
···
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text: "See: https://tour.gleam.run/functions/deprecations/".into(),
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hint: None,
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label_text: "A deprecation attribute must have a string message.".into(),
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extra_labels: vec![],
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},
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ParseErrorType::ExpectedExternalArguments => ParseErrorDetails {
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text: "".into(),
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hint: Some("See https://tour.gleam.run/advanced-features/externals/".into()),
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label_text: "This attribute is incomplete".into(),
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extra_labels: vec![],
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},
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compiler-core/src/parse/snapshots/gleam_core__parse__tests__external_with_no_arguments.snap
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compiler-core/src/parse/snapshots/gleam_core__parse__tests__external_with_no_arguments.snap
···
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---
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source: compiler-core/src/parse/tests.rs
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expression: "\n@external\npub fn one(x: Int) -> Int {\n todo\n}"
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---
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----- SOURCE CODE
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@external
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pub fn one(x: Int) -> Int {
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todo
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}
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----- ERROR
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error: Syntax error
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┌─ /src/parse/error.gleam:2:1
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│
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2 │ @external
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│ ^^^^^^^^^ This attribute is incomplete
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Hint: See https://tour.gleam.run/advanced-features/externals/
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compiler-core/src/parse/tests.rs
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compiler-core/src/parse/tests.rs